Just to add in my two cents - I'm currently vegging three inch tall clones under a 1000HPS with my rez at 2.0EC, 1500PPM of CO2, and I would never dream of letting my temps get over 85 (constant at 80 right now with no ventilation, simply a sealed room) - don't have the links handy, but although CO2 does allow you to run at slightly increased temps because of the higher metabolic rate(s) of the plant(s), going up to or above 90F is just ludicrous, IMHO, and has been proven to be another "grower's myth" in the past decade.
Of course, I'm in the third group of people who spend tons of money on their setup (out of work and bored), so I can control all these factors very, very well, but high temps are really, really something to avoid.
Good ventilation mitigates them to an extent, but your plants will be stretchier in veg and your buds will be fluffier in flower.
I go overboard on ventilation and temp/humidity control (by my own admission), but that's because of how important I feel it is.